Pistons are redstone-activated tools that push blocks in their line of direction. They can be used to make piston doors, traps and more.
When a redstone current is applied, it expands to take up two blocks in a single direction pushing blocks out of the way. Blocks that are not pushable include bedrock, extended pistons, portal stone. and portal frame. It is only able to push seven blocks.
If a piston on its side is powered by a pressure plate directly on top of the piston, then the piston will repeatedly fire in a random pattern